NPS-MOUNT RUSHMORE NATIONAL MEMORIAL
PWS ID: SD4680046 · KEYSTONE, South Dakota 57751
PFAS Detected
4 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.
Population Served
4,100
Total Violations
68
Health-Based Violations
63
Water Source
Groundwater
System Details
- System Type
- Non-Transient Non-Community
- Owner Type
- Federal
- Connections
- 19
- County
- Pennington
- School/Daycare
- No
- MCL Violations
- 63
- Monitoring Violations
- 5
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Arsenic | MCL | 63 | 2011 |
| Revised Total Coliform Rule | MON | 3 | 2022 |
| Coliform (TCR) | MR | 2 | 2010 |
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 7 of 60 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| NMeFOSAA | 6/14/2023 | <0.006 µg/L | 0.006 µg/L | Not Detected |
| 8:2 FTS | 6/14/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFBS | 6/14/2023 | 0.0032 µg/L | 0.003 µg/L | Detected |
| PFHpA | 6/14/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHxS | 6/14/2023 | 0.0208 µg/L | 0.003 µg/L | Detected |
| NEtFOSAA | 6/14/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFTA | 6/14/2023 | <0.008 µg/L | 0.008 µg/L | Not Detected |
| PFNA | 6/14/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFOS | 6/14/2023 | 0.0098 µg/L | 0.004 µg/L | Detected |
| PFOA | 6/14/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFDA | 6/14/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 9Cl-PF3ONS | 6/14/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| ADONA | 6/14/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| HFPO-DA | 6/14/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFBA | 6/14/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFTrDA | 6/14/2023 | <0.007 µg/L | 0.007 µg/L | Not Detected |
| PFPeS | 6/14/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| 11Cl-PF3OUdS | 6/14/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFUnA | 6/14/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| PFHxA | 6/14/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 6:2 FTS | 6/14/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFHpS | 6/14/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 4:2 FTS | 6/14/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| NFDHA | 6/14/2023 | <0.02 µg/L | 0.02 µg/L | Not Detected |
| PFEESA | 6/14/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMBA | 6/14/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeA | 6/14/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMPA | 6/14/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFDoA | 6/14/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| lithium | 5/3/2023 | 33.7000 µg/L | 9 µg/L | Detected |
| PFHxS | 3/18/2024 | 0.0105 µg/L | 0.003 µg/L | Detected |
| PFOS | 3/18/2024 | 0.0106 µg/L | 0.004 µg/L | Detected |
| PFTrDA | 11/7/2023 | <0.007 µg/L | 0.007 µg/L | Not Detected |
| lithium | 11/7/2023 | 29.5000 µg/L | 9 µg/L | Detected |
| 4:2 FTS | 11/7/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHpA | 11/7/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFNA | 11/7/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFOA | 11/7/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFDA | 11/7/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFDoA | 11/7/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHxA | 11/7/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFUnA | 11/7/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| 11Cl-PF3OUdS | 11/7/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 9Cl-PF3ONS | 11/7/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| ADONA | 11/7/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| HFPO-DA | 11/7/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| NMeFOSAA | 11/7/2023 | <0.006 µg/L | 0.006 µg/L | Not Detected |
| 6:2 FTS | 11/7/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| NEtFOSAA | 11/7/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 8:2 FTS | 11/7/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
Data Sources: EPA Safe Drinking Water Information System (SDWIS), Q4 2025.
PFAS data from EPA UCMR5 monitoring program (2023-2025).
This data is provided for informational purposes only.